/ Dictionary / Index E electron spin resonance: Meaning and Definition of Find definitions for: elec'tron spin' res"onance Pronunciation: [key] — Physics. Physics. the flipping back and forth between two spin directions of electrons in a magnetic field when electromagnetic radiation of the proper frequency is applied. Abbr.: ESR Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. electron-ray tube electron telescope Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language